One of the components of a circuit that steps up or steps down voltage is a reactor. For example, Patent Literature 1 discloses a reactor that is used in a converter installed in a vehicle such as a hybrid vehicle. The reactor includes a coil, an annular magnetic core where the coil is disposed, a case storing a combined product made up of the coil and the magnetic core, and a sealing resin with which the case is filled. Generally, the reactor is used as being fixed to a cooling base for cooling the coil and the like, which produce heat when being energized.
The representative case is a die casting product made of aluminum. The case is used as being fixed to the cooling base to serve as a heat dissipation path for dissipating heat from the coil and the like.